Manufacture of incandescent filaments of metallic tungsten or molybdenum for electric incandescent lamps.



ANTON LEIDERER, F ATZGERSDORF, N

DENUM FOR ELECTRIC I No Drawing. Application filed August 25,

To all whom it may concern:

Be it known that I, ANTON Lnnnann, a

subject of the Empire of Austria-Hungary, residing at No. 83 Atzgersdorf, near Vienna, Lower Austria, Austria-Hungary, have invented certain' new and useful Improvements in the Manufacture of Incandescent Filaments of Metallic Tungsten or Molybdenum for Electric Incandescent Lamps, of which the following is a specification.

The present invention relates to a new process of manufacturing incandescence filaments of metallic tungsten or molybdenum, the object being to obtain filaments which consist of perfectly pure metal in either instance.

When powdere molybdenum is wor d metallic tungsten or ked up into filaments for incandescent lamps with the use of an organic agglutinant, such as tar, levulose, gum, or the like (such being the process employed in making filaments of metallic osmium) by kneading the powdered metal and the agglutinant into a pasty mass, forming filaments from the paste by pressure and heating the filaments by passing electric current through them, the filaments obtained do not represent the metal in a pure state but consist of tungsten carbid or molybdenum earbid, as the case may be. Such filaments are not well suited to the purposes of electric incandescence lamps because they are decomposed by being heated by the electric current, and the carbid, being liberated, is deposited on the walls of the glass bulb of the lamp, either making the same impervious to light, or reducing its light transmitting capacity. When filaments of metallic tungsten or molybdenum or a mixture of both these metals are to be made to serve as the filaments of incandescence lamps, a binding material should be used which, when heat ed, vaporizes without leaving any residue whatever. Examples of binding materials or agglutinants suited to that purpose are certain aromatic substances such as camphor, chlorhydrate of pine (artificial camphor) and some others.

The process of manufactue constituting the subject of the present invention and application may 'bed as follows: The

be descr1 metals named are taken in a powdered state and, if desired, with som e alcohol added to them, and are mixed with camphor 1n the EAR VIENNA, AUSTRIA-HUNGARY.

TS 0F METALLIC TUNGSTEN OR MOLYB- NCANDESCENT LAMPS.

Specification of Letters Patent. Patented Ri 16 1915 1906. Serial No. 332,075.

proportion of about one hundred parts by weight of the metallic powder and about ten to twenty parts by weight of camphor. Thismixture gives a crumbly mass which can be easily formed into filaments by means of a rather high pressure. The filaments, consisting as they do for the most part of pure metal, are good conductors of electricity and may easily be heated in oacuo or in an atmosphere of indifferent gases, whereby the added camphor is volatilized. If the heat be gradually increased, the metallic skeleton consolidates to a homogeneous filament. By a similar process the lower (conductive) oxids of tungsten or molybdenum may be worked up into filaments, but it is preferred to use the metals themselves in powdered form.

I claim as my invention:

1. In the process of manufacturing incandescent filaments of pure refractory metals from the metals in a powdered state, a body belonging to the camphor group of aromaticsubstances which is volatile without decomposition, as agglutinant for the powdered metal for the purpose of obtaining the metal in filamentary form.

2. In the process of manufacturing incandescent filaments of pure refractory metals from the metals in a powdered state, camphor as agglutinant for the powdered metal for the purpose of obtaining the metal in a filamentary form. a

3. In the process of manufacturing incandescent filaments of pure tungsten from the metal in a powdered state, a body belonging to the camphor group of aromatic substances which is volatile Without decomposition, as agglutinant for the powdered metal for the purpose of obtaining the metal in a filamentary form.

4. In the process of manufacturing incandescent filaments of pure tungsten from the metal in a powdered state, camphor as agglutinant for the powdered metal for the purpose of obtaining the metal in a filamentary form.

5. A mixture for producing incandescent electric lamp filaments, consisting of a refractory metal in a powdered state, and a body belonging to the camphor group of aromatic substances intimately mixed therewith.

6. A mixture for producing incandescent electric lamp filaments, consisting of tungsten metal in a powdered state, and a body In witness whereof I have hereunto set belonging to the camphor groug of ai-(ilmatic my hand in presence of two witnesses. substances intimatel mixed t erewit 1 7. A mixture for roducing incandescent ANTON LEDERE'R' electric lamp filaments, consisting of tung- Witnesses: sten metal in a powdered state and camphor ALvEs'ro S. HOGUE, intimately mixed therewith. AUGUST 'FUGGER. 

